Combining Texts

All the ideas for 'A Theory of Universals', 'There are no ordinary things' and 'Alfred Tarski: life and logic'

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21 ideas

4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / g. System S4
If what is actual might have been impossible, we need S4 modal logic [Armstrong, by Lewis]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / j. Axiom of Choice IX
The Axiom of Choice is consistent with the other axioms of set theory [Feferman/Feferman]
Axiom of Choice: a set exists which chooses just one element each of any set of sets [Feferman/Feferman]
Platonist will accept the Axiom of Choice, but others want criteria of selection or definition [Feferman/Feferman]
The Trichotomy Principle is equivalent to the Axiom of Choice [Feferman/Feferman]
Cantor's theories needed the Axiom of Choice, but it has led to great controversy [Feferman/Feferman]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
A structure is a 'model' when the axioms are true. So which of the structures are models? [Feferman/Feferman]
Tarski and Vaught established the equivalence relations between first-order structures [Feferman/Feferman]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
Löwenheim-Skolem says if the sentences are countable, so is the model [Feferman/Feferman]
Löwenheim-Skolem Theorem, and Gödel's completeness of first-order logic, the earliest model theory [Feferman/Feferman]
5. Theory of Logic / K. Features of Logics / 4. Completeness
If a sentence holds in every model of a theory, then it is logically derivable from the theory [Feferman/Feferman]
5. Theory of Logic / K. Features of Logics / 7. Decidability
'Recursion theory' concerns what can be solved by computing machines [Feferman/Feferman]
Both Principia Mathematica and Peano Arithmetic are undecidable [Feferman/Feferman]
7. Existence / D. Theories of Reality / 10. Vagueness / d. Vagueness as linguistic
Vague predicates lack application; there are no borderline cases; vague F is not F [Unger, by Keefe/Smith]
8. Modes of Existence / B. Properties / 1. Nature of Properties
Properties are universals, which are always instantiated [Armstrong, by Heil]
8. Modes of Existence / B. Properties / 6. Categorical Properties
Even if all properties are categorical, they may be denoted by dispositional predicates [Armstrong, by Bird]
8. Modes of Existence / D. Universals / 2. Need for Universals
Universals explain resemblance and causal power [Armstrong, by Oliver]
8. Modes of Existence / E. Nominalism / 3. Predicate Nominalism
It doesn't follow that because there is a predicate there must therefore exist a property [Armstrong]
9. Objects / A. Existence of Objects / 5. Simples
There are no objects with proper parts; there are only mereological simples [Unger, by Wasserman]
9. Objects / F. Identity among Objects / 4. Type Identity
The type-token distinction is the universal-particular distinction [Armstrong, by Hodes]
9. Objects / F. Identity among Objects / 5. Self-Identity
A thing's self-identity can't be a universal, since we can know it a priori [Armstrong, by Oliver]